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Gis basic-2

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Gis basic-2

  1. 1. GIS DR. B. L. SINHA Scientist/ Assistant Professor (Soil Water Engineering) DKS College of Agriculture and Research Station Indira Gandhi Krishi Vishwavidyalay (Chhattisgarh) Bhatapara
  2. 2. GISGIS Data Decisions Science M anagem ent (Geographic Information Systems)
  3. 3. Roger F. Tomlinson, OC (17 November 1933 – 7 February 2014) was an English geographer and the primary originator of modern computerised geographic information systems (GIS), and has been acknowledged as the "father of GIS."
  4. 4. GIS--What is it? • Geographic/Geospatial Information – information about places on the earth’s surface – knowledge about “what is where when” (Don’t forget time!) – Geographic/geospatial: synonymous • GIS--what’s in the S? – Systems: the technology – Science: the concepts and theory – Studies: the societal context
  5. 5. Geographic Information Technologies • Global Positioning Systems (GPS) – a system of earth-orbiting satellites which can provide precise (100 meter to sub-cm.) location on the earth’s surface (in lat/long coordinates or equiv.) • Remote Sensing (RS) – use of satellites or aircraft to capture information about the earth’s surface – Digital ortho images a key product (map accurate digital photos) • Geographic Information Systems (GISy) – Software systems with capability for input, storage, manipulation/analysis and output/display of geographic (spatial) information GPS and RS are sources of input data for a GISy. A GISy provides for storing and manipulating GPS and RS data.
  6. 6. GI Systems, Science and Studies Which will we do? • Systems – technology for the acquisition and management of spatial information • Science – comprehending the underlying conceptual issues of representing data and processes in space-time – the theory and concepts behind the technology Introduce enough of the science to apply the systems correctly and understand their capabilities and limitations • Studies – understanding the social, legal and ethical issues associated with the application of GISy and GISc
  7. 7. Defining Geographic Information Systems (GIS) • The common ground between information processing and the many fields using spatial analysis techniques. (Tomlinson, 1972) • A powerful set of tools for collecting, storing, retrieving, transforming, and displaying spatial data from the real world. (Burroughs, 1986) • A computerised database management system for the capture, storage, retrieval, analysis and display of spatial (locationally defined) data. (NCGIA, 1987) • A decision support system involving the integration of spatially referenced data in a problem solving environment. (Cowen, 1988)
  8. 8. An Inelegant Definition for GISy A system of integrated computer-based tools for end-to- end processing (capture, storage, retrieval, analysis, display) of data using location on the earth’s surface for interrelation in support of operations management, decision making, and science. • set of integrated tools for spatial analysis • encompasses end-to-end processing of data – capture, storage, retrieval, analysis/modification, display • uses explicit location on earth’s surface to relate data • aimed at decision support, as well as on-going operations and scientific inquiry
  9. 9. Geographic Information System: • A map with a database behind it. • A virtual representation of the real world and its infrastructure. • A consistent “as-built” of the real world, natural and manmade Which is • queried to support on-going operations • summarized to support strategic decision making and policy formulation • analyzed to support scientific inquiry
  10. 10. How GIS differs from Related Systems • DBMS--typical MIS data base contains implicit but not explicit locational information – city, county, zip code, etc. but no geographical coordinates – is 100 N. High around the corner or across town from 200 E Main? • automated mapping (AM) --primarily two-dimensional display devices – thematic mapping (choropleth,etc such as SAS/GRAPH, DIDS, business mapping software) unable to relate different geographical layers (e.g zip codes and counties) – automated cartography--graphical design oriented; limited database ability • facility management (FM) systems-- – lack spatial analysis tools • CAD/CAM (computer aided design/drafting)--primarily 3-D graphic creation (engineering design) & display systems – don’t reference via geographic location • CAD sees the world as a 3-D cube, GIS as a 3-D sphere – limited (if any) database ability (especially for non-spatial data) • scientific visualization systems--sophisticated multi-dimensional graphics, but: – lack database support – lack two-dimensional spatial analysis tools
  11. 11. Why Study GIS? • 80% of local government activities estimated to be geographically based – plats, zoning, public works (streets, water supply, sewers), garbage collection, land ownership and valuation, public safety (fire and police) • a significant portion of state government has a geographical component – natural resource management – highways and transportation • businesses use GIS for a very wide array of applications – retail site selection & customer analysis – logistics: vehicle tracking & routing – natural resource exploration (petroleum, etc.) – precision agriculture – civil engineering and construction • Military and defense – Battlefield management – Satellite imagery interpretation • scientific research employs GIS – geography, geology, botany – anthropology, sociology, economics, political science – Epidemiology, criminology
  12. 12. Where Most UT-D Students Come From/Go To The major areas of GIS application • Local Government – Public works/infrastructure management (roads, water, sewer) – Planning and environmental management – property records and appraisal • Real Estate and Marketing – Retail site selection, site evaluation • Public safety and defense – Crime analysis, fire prevention, emergency management, military/defense • Natural resource exploration/extraction – Petroleum, minerals, quarrying • Transportation – Airline route planning, transportation planning/modeling • Public health and epidemiology • The Geospatial Industry – Data development, application development, programming
  13. 13. Examples of Applied GIS • Urban Planning, Management & Policy – Zoning, subdivision planning – Land acquisition – Economic development – Code enforcement – Housing renovation programs – Emergency response – Crime analysis – Tax assessment • Environmental Sciences – Monitoring environmental risk – Modeling stormwater runoff – Management of watersheds, floodplains, wetlands, forests, aquifers – Environmental Impact Analysis – Hazardous or toxic facility siting – Groundwater modeling and contamination tracking • Political Science – Redistricting – Analysis of election results – Predictive modeling • Civil Engineering/Utility – Locating underground facilities – Designing alignment for freeways, transit – Coordination of infrastructure maintenance • Business – Demographic Analysis – Market Penetration/ Share Analysis – Site Selection • Education Administration – Attendance Area Maintenance – Enrollment Projections – School Bus Routing • Real Estate – Neighborhood land prices – Traffic Impact Analysis – Determination of Highest and Best Use • Health Care – Epidemiology – Needs Analysis – Service Inventory
  14. 14. What GIS Applications Do: manage, analyze, communicate • make possible the automation of activities involving geographic data – map production – calculation of areas, distances, route lengths – measurement of slope, aspect, viewshed – logistics: route planning, vehicle tracking, traffic management • allow for the integration of data hitherto confined to independent domains (e.g property maps and air photos). • by tieing data to maps, permits the succinct communication of complex spatial patterns (e.g environmental sensitivity). • provides answers to spatial queries (how many elderly in Richardson live further than 10 minutes at rush hour from ambulance service?) • perform complex spatial modelling (what if scenarios for transportation planning, disaster planning, resource management, utility design)
  15. 15. GIS System Architecture and Components Data Input Query Input Geographic Database Output: Display and Reporting Transformation and Analysis
  16. 16. Knowledge Base for GIS GIS Application Area: public admin. planning geology mineral exploration forestry site selection marketing civil engineering criminal justice surveying Computer Science/MIS graphics visualization database system administration security Geography and related: cartography geodesy photogrammetry landforms spatial statistics. The convergence of technological fields and traditional disciplines.
  17. 17. The GIS Data Model
  18. 18. The GIS Data Model: Purpose • allows the geographic features in real world locations to be digitally represented and stored in a database so that they can be abstractly presented in map (analog) form, and can also be worked with and manipulated to address some problem (see associated diagrams)
  19. 19. GIS Data Model A layer-cake of information
  20. 20. The GIS Data Model: Implementation Geographic Integration of Information Digital Orthophoto Streets Hydrography Parcels Buildings Zoning Utilities Administrative Boundaries • Data is organized by layers, coverages or themes (synonomous concepts), with each layer representing a common feature. • Layers are integrated using explicit location on the earth’s surface, thus geographic location is the organizing principal.
  21. 21. The GIS Model: example roads hydrology topography Here we have three layers or themes: --roads, --hydrology (water), --topography (land elevation) They can be related because precise geographic coordinates are recorded for each theme. longitude latitude longitude longitude latitude latitude Layers are comprised of two data types •Spatial data which describes location (where) •Attribute data specifing what, how much,when Layers may be represented in two ways: •in vector format as points and lines •in raster(or image) format as pixels All geographic data has 4 properties: projection, scale, accuracy and resolution
  22. 22. Spatial and Attribute Data • Spatial data (where) – specifies location – stored in a shape file, geodatabase or similar geographic file • Attribute (descriptive) data (what, how much, when) – specifies characteristics at that location, natural or human- created – stored in a data base table GIS systems traditionally maintain spatial and attribute data separately, then “join” them for display or analysis – for example, in ArcView, the Attributes of … table is used to link a shapefile (spatial structure) with a data base table containing attribute information in order to display the attribute data spatially on a map
  23. 23. Representing Data with Raster and Vector Models Raster Model • area is covered by grid with (usually) equal-sized, square cells • attributes are recorded by assigning each cell a single value based on the majority feature (attribute) in the cell, such as land use type. • Image data is a special case of raster data in which the “attribute” is a reflectance value from the geomagnetic spectrum – cells in image data often called pixels (picture elements) • Vector Model The fundamental concept of vector GIS is that all geographic features in the real work can be represented either as: • points or dots (nodes): trees, poles, fire plugs, airports, cities • lines (arcs): streams, streets, sewers, • areas (polygons): land parcels, cities, counties, forest, rock type Because representation depends on shape, ArcView refers to files containing vector data as shapefiles
  24. 24. 0 1 2 3 4 5 6 7 8 9 0 R T 1 R T 2 H R 3 R 4 R R 5 R 6 R T T H 7 R T T 8 R 9 R Real World Vector Representation Raster Representation Concept of Vector and Raster line polygon point
  25. 25. Images—dumb rasters (although they look good!) Smart Raster—5 feet grids Smart Vector—Pavement polygons Dumb Images & Smart GIS Data
  26. 26. Projection, Scale, Accuracy and Resolution the key properties of spatial data • Projection: the method by which the curved 3-D surface of the earth is represented by X,Y coordinates on a 2-D flat map/screen – distortion is inevitable • Scale: the ratio of distance on a map to the equivalent distance on the ground – in theory GIS is scale independent but in practice there is an implicit range of scales for data output in any project • Accuracy: how well does the database info match the real world – Positional: how close are features to their real world location? – Consistency: do feature characteristics in database match those in real world • is a road in the database a road in the real world? – Completeness: are all real world instances of features present in the database? • Are all roads included. • Resolution: the size of the smallest feature able to be recognized – for raster data, it is the pixel size The tighter the specification, the higher the cost.
  27. 27. Examples
  28. 28. Street Network layer: lines Land Parcels layer: polygons Raster (image) Layer Digital Ortho Photograph Layer: Digital Ortho photo: combines the visual properties of a photograph with the positional accuracy of a map, in computer readable form. Vector Layers Layers Projection: State Plane, North Central Texas Zone, NAD 83 Resolution: 0.5 meters Accuracy: 1.0 meters Scale: see scale bar 0 1500 3000 Feet
  29. 29. Overlay based on Common Geographic Location
  30. 30. Parcels within a half mile buffer of Park and Central Photographic Image Scanned Drawing Analysis Data Table
  31. 31. Anatomy of a GIS Database: City of Plano Vector Layers Attribute Tables Raster Layers
  32. 32. Course Content Part I: Overview • Fundamentals of GIS • Hands-on Intro to ArcGIS – (lab sessions @ 1:00-4:00 or 7:00-10:00pm in GR 3.602) Part II: Principles • Terrestrial data structures – representing the real world • GIS Data Structures – representing the world in a computer • Data Quality – An essential ingredient Part III: Practice • Data Input: preparation, integration, and editing • Data analysis and modeling • Data output and application examples Part IV: The Future • Future of GIS
  33. 33. Hands-on Projects• Locating a Day-care – intro to GIS capabilities – illustration of a major application: site selection • Texas Demographic growth – manipulation of data and mapping principles – another major application: analysis of spatial patterns with polygon data • Geocoding Housing Sales, or Analyzing Earthquake Locations – techniques and data requirements for geocoding and point patterns – another application: geocoding/address matching • Creating a Census Tract layer, or a Geological Map – editing and creating topologically consistent data – how new data layers can be created • Pipeline Routing – data selection, buffering and spatial analysis – another major application: corridor studies
  34. 34. Next Week An Introduction to GIS Software Meet @ 7:00 on Tuesday in GR 3.602 or on Wednesday in GR 3.206 If you have already got your UTD “netid” be sure to bring it and your password. Otherwise, we will get you set up when we meet.
  35. 35. Appendix GIS Software Packages
  36. 36. Software for GIS: The Main Players • ESRI, Inc., Redlands, CA – clear market leader with about a third of the market – originated commercial GIS with their ArcInfo product in 1981 – privately owned by Jack Dangermond, a legend in the field – Strong in gov., education, utilities and business logistics • MapInfo, Troy N.Y. – Aggressive newcomer in early 1990s, but now well-established. – Strong presence in business, especially site selection & marketing, and telecom • Intergraph (Huntsville, AL) – origins in proprietary CAD hardware/software – Older UNIX-based MGE (Modular GIS Environment) evolved from CAD – Current GeoMedia was the first true MS Windows-based GIS – strong in design, public works, and FM (facilities management), but weakening • Bentley Systems (Exton, PA) – MicroStation GeoGraphics, originally developed with Intergraph, is now their exclusive and main product.. – Strong in engineering; advertises itself as “geoengineering” • Autodesk (San Rafael, CA) – Began as PC-based CAD, but now the dominant CAD supplier – First GIS product AutoCAD Map introduced in 1996 – Primarily small business/small city customer base The main two “pure GIS” companies.
  37. 37. Software for GIS: other players Vector GIS • Smallworld Systems (Englewood, CO) – first to use OO (early ‘90s), but failed to compete as established vendors did same – Purchased by GE in 2000 – emphasis on FM & utilities • Manifold (CDA International Corp): – low cost, but low market share • Maptitude (Caliper Corp, Newton, MA): – another low cost one Raster GIS • ERDAS/Imagine – long established leader – acquired by Leica Geosystems in 2001 • ER MAPPER – aggressive newcomer originating in Australia • Envi, – relative newcomer, radar specialization – acquired by Kodak in 2000 • PCI--Geomatica – long-term Canadian player • CARIS – newer Canadian entry • GRASS (Rutgers Univ.) – Classic old-timer originally developed by US Army Construction Engineering Research Lab(CERL) in Champaign, IL; – army ended dev. & support in 1996 but assumed by Baylor University. • IDRSI (Clark Univ) – pioneering, university-developed package
  38. 38. ESRI Product Line-up: ArcGIS client products (Fall 2007) ArcReader (“adobe acrobat” for maps) & ArcExplorer (spatial data viewer) – Free viewers for geographic data. ArcGIS 9.x Desktop: two primary modules (MS only) 1. ArcMap: for data display, map production, spatial analysis, data editing 2. ArcCatalog: for data management and preview ArcToolbox, for specialized data conversions and analyses, available as a window in both Available capabilities within these modules are “tiered” in three levels • ArcView: viewing, map production, spatial analysis, basic editing: • ArcEditor: ArcView, plus specialized editing: • ArcInfo: ArcView & ArcEditor plus special analyses and conversions: Extensions: for special apps.: Spatial Analyst, 3D Analyst, Geostatistics, Business Analyst, etc. ArcObjects: to build specialized capabilities within ArcMap or ArcCatalog using VB for Applications ArcGIS Workstation (for UNIX and MS) – the old command line ArcInfo 7.1 ArcGIS Engine (MS NT/2000/XP) – Set of embeddable GIS components (ArcObjects software objects) for use in building custom applications – Runs under Windows, Unix and Linux, with support for Java, C++, COM and .NET – Replaces MapObjects which were based upon a previous generation of GIS objects Notes: ArcView 3.3 the only GUI option for UNIX. ArcGIS 8 released 2000 to integrate two previous standalone products: ArcView and ArcInfo ArcGIS 9 released 2004 providing the full capability that should have been in ArcGIS 8!!! --full support for all data types (coverages, shapefiles, geodatabases) --full support for all previous geoprocessing analyses --Modelbuilder for scripting and repetitive processing --ArcEngine for building custom applications
  39. 39. ArcGIS Server: three tiers of capability Data services: ArcSDE (Spatial Database Engine) • middleware to support spatial data storage in standard DBMS on server • Supports all major industry databases: – Oracle, SQL-Server, IBM DB2, Ingres Map services: ArcIMS (Internet Map Server) • Provides maps and simple query to a user without a desktop GIS • Accessed via web interface Analytic services: • Permits the creation of server-based specialized GIS applications • Provides full range of GIS capabilities to a user without a desktop GIS • Accessed via web interface (prior to 9.2 these were sold as three separate products) ArcGIS On-line Services – On-line services made available on the Internet with a subscription – Normally charged on a “per transaction” basis, but can be flat fee – built and operated by ESRI (or other others), usually based on ArcGIS Server ESRI Product Line-up: ArcGIS server products (Fall 2007)
  40. 40. Clients ESRI ArcGIS SystemESRI ArcGIS System FilesFiles (Personal Geodatabase,(Personal Geodatabase, Shapefiles, Coverages,Shapefiles, Coverages, Grids, tins, etc)Grids, tins, etc) ArcSDE Services Database storage/access DatabasesDatabases Multi-user GeodatabasesMulti-user Geodatabases (in Oracle, SQL Server,(in Oracle, SQL Server, IBM DBII, etc)IBM DBII, etc) ArcInfo ArcEditor ArcView ArcIMS Services Map display & query ArcExplorer Browser InternetArcPad ArcEngine/ ArcObjects Application Development & Customization c: ArcGIS Workstation Consistent interface Increasing capability ArcMap ArcCatalog ArcToolbox ArcMap ArcCatalog ArcToolbox ArcMap ArcCatalog ArcToolbox Source: ESRI with mods. Handheld/Wireless $ ArcServer Services Full GIS analysis
  41. 41. Future Generic GIS Internet Enterprise Web Server DatabasesDatabases BrokerBroker BrowsersBrowsers Web ApplicationsApplications ServicesServices ( built on( built on .Net, SOAP/XML, Java API).Net, SOAP/XML, Java API) Source: Reza Wahadj, CSIG04, with mods. Dallas DurbanDelhi

Editor's Notes

  • --the common theme is obviously spatial--that is to say, refenced to the earth’s surface
    --tomlinson: very general ‘common ground’
    --Burroughs: ‘ tool box’, but how linked together?
    --NCGIA ‘dbms’ for spatila data, but also adds the concept of process--capture, store, analze and display
    --Cowen: adds (1)decison sipport/solve problem perspective and (2) integration
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